Draft switch



P 1949- A. F. GEISEL 2,480,847

DRAFT SWITCH Filed June 5, 1946 IN V EN TOR.

25 BY fi/urf? 519/35/ Patented Sept. 6, 1949 DRAFT SWITCH Arthur F. Geisel, Milwaukee, Wis., assignor to Perfex Corporation, Milwaukee, Wis., a corporation of Wisconsin Application June 5, 1946, Serial N 0. 674,543

This invention relates generally to a switching mechanism for controlling an electric circuit and more particularly to a switching mechanism responsive to changes in condition, such as pressure or temperature, for controlling a condition regulator.

In the preferred embodiment of this invention, herein disclosed, the switching mechanism is adapted to respond to changes in the amount of draft air being supplied to a furnace for the burning of fuel. Upon a change in the amount of draft air supplied, the proper electrical circuit is completed to a damper operator which in turn moves a draft damper in a direction to bring the amount of draft air supplied back to the desired value.

An object of my invention is to provide a switch mechanism of the character described which has a structure of simple character and design and can be manufactured at a relatively low cost.

A further object of my invention is to provide a device of the character described which will successfu ly operate for a long period of time without frequent readjustments.

A further object of my invention is to provide a device of the character described which is capable of ad ustment for operation within relatively close limits.

Other objects of this invention will appear from the following description and the appended claims.

For a full disclosure of the invention, reference is made to the accompanying drawings in which,

Fig. 1 represents a front view partly in section with the cover removed; and

Fig. 2 represents a sideview, in section, with the cover removed.

The reference number Ill refers to a mounting base with upturned edges ll. Fastened to the mounting base are three mounting brackets l2, l3, and I4 with suitable mounting holes therein. Four tubular mounting spacers (two of which l5 and I6 are shown) are fastened to the mounting base In by means of bolts l1, I8, [9, and which are turned into screw-threaded holes in the mounting base in. A flanged dish member 2! and a similar dish member 22 form a diaphragmchamber which is mounted on said four spacers. The bolts l1, l8, l9 and 20 pass through suitable holes in the flanges of the dished members. An inlet chamber is provided consisting of the deadend tubular section 28, which passes through a cutaway portion of the upturned edge II and is fastened to the mounting-base l0 by means of 4 Claims- (Cl. 200-83) the screws 29 and 30.

The tubular section 28 is threaded at 3! to receive an inlet pipe. A tube 32 extends from tubular section 28 through an opening in the flanged dish member 22. An inlet passage is thus provided from the tubular section 28 through the inlet tube 32 into the diaphragm-chamber.

The diaphragm-chamber formed by the two dish members 2| and 22 contains a flexible diaphragm clamped between the two flanged, dish members 2! and 22 and the diaphragm mounting spacers 2?. Two diaphragm stiffening membars 33 and 34 are fastened to the diaphragm at 35, 36, and 31. The stiffening members 33 and 34 are provided with outwardly extending edges, and are beaded at 53 and 54 for additional rigidity. The diaphragm is thus so constructed that any flexing or bending of the diaphragm takes place at the flexible portions 39 and 43.

A mounting lug 4| is riveted to the stiffening member 33. A link member 43 is riveted to the mounting lug 4|, and extends through an opening 44 in the front dish member 2!.

A flanged supporting member 52 is secured to the front dish member 2| at 55, 56, 51, and 58. A U-shaped bracket 48, carrying the pivot pin 49 and spacers 5H and 5!, is fastened to the supporting member 52 as shown in Fig. 1. A lever member 45 is pivoted near one of its ends on the pivot pin 49, and at its other end on the pivot pin 41 which is carried by the link member 43. A U-shaped switch supporting member 58 is fastened to the front dish member 2! at 69, l9, 1!, and 12. A bracket 66 is mounted at E1 on the switch supporting member 58 and carries a spring hinge 64. An operating member so is fastened, at one of its ends, to the spring hinge 64, The operating member 66 has an in-turned portion BI, and a pivot pin 59 extending therefrom. The pivot pin 59 extends through an elongated opening 62 in lever member 45. An enlarged opening in the in-turned portion 6| of the operating member allows the pivot pin 4': to extend loosely through this portion, as shown in Fig. 1.

Switch actuating arms 1.; and T4 are mounted on the operating member 60, with a spacer 16 between the resilient member 64 and the actuating arm 14. Tapped holes in the switch actuating arms 13 and 14 receive the actuator members 11 and 18. Actuator members I? and '18 are adapted to engage the thrust members 19 and of the normally open, enclosed switches 8| and 82 respectively. The switches 8| and 82 are so designed that a small inward movement of the thrust members 19 and 80 will close their nor- 3 mally open contacts. These switches 8| and 82 form no part of the present invention. The switches 8| and 82 are fastened to the supporting member 68 by means of the bolts I01 and I02 4 crating member 60 causes the actuating arm 14 and actuator member 18 to close the contacts of the normally open switch 82.

I have herein shown and described certain emwhich are screw-threaded into the spacing mem- 5 bodiments of my invention for the purpose of exber I04. The actuator member 18 extends plaining its principles and showing its applicathrough an opening in the switch supporting tion. Numerous modifications may be made member 68 and is fitted with a manual setting without departing from the principles of the inknob 83, an indicating pointer 84, and stops 85 vention which are included in the following and 86 (see Fig. 1). Rotating the manual setclaims. ting knob 83 varies the amount of the movement What is claimed is: of the actuating arm 14 necessary to close switch 1. In a condition responsive switch, an operat- 82, thus providing a difierential adjustment. lng member with two switch actuating arms op- It will be noted that actuator 11 is in threaded positely extending therefrom, resilient mounting engagement with actuating .arm 13 for proper 15 means attached to said operating member, difierfactory adjustment of the amount of moveential adjusting means attached to one of said ment of the actuating arm 13 necessary to close switch actuating arms, switching means adjacent switch 81. each of said switch actuating arms, one of said One end of a tension spring 81 is fastened to switching means adapted to be actuated by one the lever member 45, as at 88. The other end of of said switch actuating arms upon movement of the Spring 81 is fastened to a spring holder 89. said operating member in one direction, the other Threaded through the spring holder 39 is an adof said switching means adapted to be actuated justing screw to which extends through the supby the other of said switch actuating arms upon porting member 52. The adjusting screw =90 is movement of said operating member in another provided with a slotted head 91., lock nuts 92 and direction, condition responsive means, moving 93, and compressionspr g 94. The sp holdmeans for moving said operating member when er 89 is prevented from turning upon rotation of said condition responsive means responds to a the adjusting screw 9 y means of n eXtendine change in condition, and adjustable resisting portion 9 AS y best be S in the means resisting movement of said operating outer end of the extendin portion 95 is fitted member by said moving means. into a longitudinal slot 96in the s pp g mem- 2. In a pressure switch, an operating member ber .52. Rotation of the adjusting screw 90 rewith switch actuating arms extending therefrom, suits in-cha ging the pos t n-0 the Spring holder resilient mounting means attached to said operat- 89 and consequently changing the tension in the ing member, differential adjusting means screw sp ng 8 1. This provides rang djustment. 5 threaded into one of said switch actuating arms,

A bracket 9 faste e to he eupperting differential adjustment indicating means associb 5 has a threaded opening 98 to receive a ated with said differential adjusting means, said Cover melmting screw 99 (Shown by broken lines diirerentialadjustment indicating means consistin Fi The Cover mounting screw -99 holds ingof an indicatin pointer rotated betweenstop in place a cover .105) (shown by broken lines in members, switchingmeans adjacent each of said Fig. 2).

.In the form disclosed, the switchis adapted to react to variations in draft pressure. The portion of the diaphragm chamber to the left of the diaphragm (as viewed in Fig. 2) is at atmospheric pressure. The portion of the diaphragm chamber to the right of the diaphragmis .at draft ,pressure which will be less than atmospheric pressure. The resulting force tending to move the diaphragm to the right 'is balanced by the tension spring 81, whose pull is adjusted by means of the adjusting screw 99 to a value equal to the difference between atmospheric pressure and the desired draft pressure. When spring -8'l is so adjusted, the diaphragm and the operatingmemloer 60 are in their neutral position and neither switch 8] nor 82 is actuated to its closed position. Upon an increase in draft the pressure .on the right of the diaphragm (as viewed in Fig 2) .decreasesand the diaphragm is moved to the .right, This motion is transmitted to the operating member 610 through the link member 43, lever member and pin '59. The resulting slight clockwise rotation of the operating member causes the actuating arm 13 and actuator member TI to close the contacts of the normally open switch 8]. With the diaphragm at its neutral point, that with the draft pressure plus the pull of the tension spring .8! just equal to atmospheric pressure,

the draft should decrease, the pressure .in the diaphragm chamber to the right of the diaphragm will increase. The resulting movement of the diaphragm to the left (as viewed in Fig. 2) causes a slight counterclockwise rotation of the operating member 6.0. This movement of the opswitch actuating arms and adapted to be actuated by said switch actuating arms upon movement of said operating member, pressure responsive means, moving means for moving said operating 45 member when said pressure responsive means responds to a change in pressure, and adjustable resisting means resisting movement of said operating member by said moving means.

3. In a condition responsive switch, an oper .50 ating member with switch actuating arms extend-- ing therefrom, resilient mounting means attached to said operating member, differential adjusting means screw-tlueaded into .one of said switch actuating arms, differential adjustment indicating 55 means associated with said difierential adjusting means, said difierential adjustment indicating means consisting of an indicating pointer rotated between stop members, switching means adjacent each of said .switc-h actuating arms and adapted to to beactuated by said switch actuating arms upon movement .of said operating member, condition responsive means, moving means for moving said operating member when said condition respon sive means responds to a change in condition, and adjustable resisting means resisting movement of said operating member by said moving means.

4. In a condition responsive switch, an operating member with two switch actuating arms 0ppositely extending therefrom, resilient mounting means attached to said operating member, diiferential adjusting means attached to one of switch actuating arms, switching means adjacent each of said switchactuating arms, one of said switching means adapted to be actuated :by one of said switch actuating arms upon movement of said operating member in one direction, the other of said switching means adapted to be actuated by the other of said switch actuating arms upon movement of said operating member in another direction, condition responsive means, moving means for moving said operating member when said condition responsive means responds to a change in condition, said moving means comprising a first member operatively secured to said condition responsive means, a second member having a stationary pivotal mounting, said second member having a movable pivotal connection with said first member, said operating member also having a movable pivotal connection with said second member, and adjustable resisting means resisting movement of said operating member by said moving means.

ARTHUR F. GEISEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

